Abstract - We propose a novel method of message security using trust-based multi-path routing. Simulation results, coupled with theoretical justification, affirm that the proposed solution is much more secured than the traditional multi-path routing algorithms. We propose a method to securely route messages in an ad-hoc network using multi-path routing and trustworthiness of the nodes. Hence, we aim at addressing the issues underlying message confidentiality, message integrity and access control. We combine multi-path routing and trust with soft encryption technology to propose a scheme which is much more secure than traditional multi-path algorithms. By soft encryption, we mean having encryption methods, but are more efficient in terms of performance and require less resource.

A mobile ad hoc network (MANET) is a kind of wireless ad hoc network, and is a self-configuring network of mobile routers (and associated hosts) connected by wireless links – the union of which form an arbitrary topology. The routers are free to move randomly and organize themselves arbitrarily; thus, the network’s wireless topology may change rapidly and unpredictably. Mobile ad hoc networks (MANETs) are composed of a set of stations (nodes) communicating through wireless channels, without any fixed backbone support. With the advancement in radio technologies like Bluetooth, IEEE 802.11 or hiperlan, a new concept of networking has emerged which makes wireless networks increasingly popular in the computer industry. This is particularly true within the past decade, which has seen wireless networking being adapted to enable mobility.

Later on numbers of different protocol have been proposed as a routing solution for mobile ad hoc networks. These different routing techniques classified as proactive, reactive and hybrid routing protocols. Reactive routing protocols have been found to be user friendly and efficient when compared to other routing protocols. The main boon of Reactive routing protocols when compared with Proactive and Hybrid routing protocols is the relatively unconditional low storage requirements, higher mobility and the availability of routes when needed. There are a variety of reactive routing protocols such as AODV, DSR, LAR1, LMR, ABR, SSI, TORA, RDMAR, MSR, AOMDV, MRAODV, ARA. Most of the multipath routing protocols like AOMDV, MP-OLSR and MP-DSR are the extension of unipath protocols like AODV, OLSR and DSR. In these protocols we use the DSR in this paper. DSR is the next generation pure reactive routing protocol for MANETs. It was proposed for the first time by Johnson and Maltz [5] in order to provide routing with minimum overhead while adapting to the network dynamics.

DSR is undergoing fast evolution thanks to the many optimizations integrated into it. DSR is based on a pure reactive approach and operates using two simple and complementary mechanisms: route discovery and route maintenance. In this paper We propose a novel method of message security using trust-based multi-path routing we propose a method to securely route messages in an ad-hoc network using multi-path routing and trustworthiness of the nodes. We aim at addressing the issues underlying message confidentiality, message integrity and access control.

2. RELATED WORKS

Security in MANETs has been a topic of much discussion in the last few years. There are a plenty of works available in the literature that discuss security in MANETs. But efficiently providing complete message security in such networks still remains an open issue.

Much research work has been done to make the route discovered by Dynamic Source Routing (DSR) secure. A Trust based multi path DSR protocol is proposed by Poonam et al. [11] in which uses multi-path forwarding approach. In this approach each node forwards the RREQ if it is received from different path. Through this method detect and avoid misbehaving nodes which were previously included due to vulnerability in DSR route discovery. In the traditional DSR protocol [5] when a node receives a RREQ packet, it checks if it has previously processed it, if so it drops the packet. A misbehaving node takes advantage of this vulnerability and forwards the RREQ fast so that the RREQ from other nodes are dropped and the path discovered includes itself. In their protocol each node broadcast the packet embedding trust information about the node from which the packet is receive. At the source node a secure and efficient route to the destination is calculated as weighted average of the number of nodes in the route and their trust values.

All the existing models have one or more of the following limitations. Most of the methods use the traditional DSR request discovery model, in which a node drops a RREQ packet, if it has previously processed it. A misbehaving node takes advantage of this and forwards the RREQ packet fast so that the RREQ received from other nodes, which arrive later, are dropped and the path discovered includes itself. Most of the trust based routing protocols have used forward trust model to find the path from source to destination. In this model trust is embedded only in the RREQ packet when it is forwarded. So each node evaluates only its previous node and the source node evaluates all the nodes involved in path. But we believe that the trust is asymmetric, so mutual trust information should be used. In watch dog and pathrater approach the trust values are not updated based on node behavior, rather they are updated periodically. Such periodic updates are not able to quantify the misbehaving nodes. Therefore the path discovered includes misbehaving nodes. All of these possible vulnerabilities have been taken care of in [11]. The authors have designed a secure routing protocol, called Trust based multi path DSR protocol, which depends on two-way effort of the node by embedding trust to find an end-toend secure route free of misbehaving nodes. This protocol has a drawback routing overhead is very high compared to traditional DSR due to broadcasting of RREQ packet. The other drawback is that all the one hop neighbors of destination after receiving first RREQ propagate to destination and also among them. Then this results in discarding the RREQ packet from most of the other paths to the destination node.

3. GLOMOSIM

Glomosim is a library-based sequential and parallel simulator for wireless networks. This has been developed using PARSEC, a C-based parallel simulation language. Glomosim can be modified to add new protocols and applications to the library. Therefore Glomosim is a good choice for implementing the different traffic sources.

4. TRUST BASED MULTI-PATH ROUTING WITH SOFT ENCRYPTION TECHNOLOGY

We propose a method to securely route messages in an ad-hoc network using multi path routing and trustworthiness of the nodes. Hence, we aim at addressing the issues underlying message confidentiality, message integrity and access control. We divide the message into different parts and encrypt these parts using one another. We then route these parts separately using different paths between a pair of source-destination nodes. An intermediate node can access different parts on the basis of its trustworthiness. That is, a more trusted node is allowed to feature in more paths than a less trusted node and hence access to more message parts than a less trusted node. This feature allows the routing algorithm to avoid nodes that are more likely to attempt ‘breaking-in’ the encryption. In addition, suspected nodes which have high computation power and are hence likely to be more successful in cryptanalysis can be given less parts to stymie their plans. Since establishment of trust also requires cryptographic key exchange, we use a soft approach to trust. Trust levels of peer nodes of the network are found using effort return based trust model. We use a variation of the model, which uses a combination of derived trust and reputation to estimate trust values of a node.

We combine multi-path routing and trust with soft encryption technology to propose a scheme which is much more secure than traditional multi-path algorithms. Networks using the DSR protocol have been connected to the internet. DSR can interoperate with mobile IP, and nodes using mobile IP and DSR have seamlessly migrated between WLANs, cellular data services, and DSR mobile ad hoc etworks. The DSR protocol include easily guaranteed loop-free routing, support for use in networks containing unidirectional links, use of only “soft state” in routing, and very rapid recovery when routes in the network change. This is the reason for preparing to the DSR protocol.